Atlas V blasts off with NASA mission to asteroid Bennu

Update: Liftoff! OSIRIS-REx is on its way to Bennu.

Scientists call it a high-five or kiss.

It’s the critical moment four years from now when a NASA probe, scheduled to launch from Cape Canaveral before sunset Thursday (Sept. 8), is expected to stretch out a robotic arm and gently touch the primitive asteroid Bennu.

If the five-second contact goes as planned, the arm will suck up at least two ounces of loose gravel and dust from the space rock’s surface, then store it in a small capsule slated to drop back down to the Utah desert in 2023.

The pristine material — to be the largest sample returned from space since the Apollo moon landings — may hold water ice and organic molecules like those thought to have helped seed life on Earth, and perhaps elsewhere.

“We’re going to an asteroid that represents the first building blocks of the planets in our solar system,” said Dante Lauretta, lead scientist from the University of Arizona for the $800 million mission named OSIRIS-REx. “We believe these hold precious organic molecules that were the precursors to life on the planet.”

The mission’s name is an acronym for “Origins, Spectral Interpretation, Resource Identification and Security-Regolith Explorer.”

It is NASA’s first attempt to collect and bring back an asteroid sample, following a Japanese mission’s 2010 return of grains from the asteroid Itokawa.

A 189-foot United Launch Alliance Atlas V rocket is scheduled to lift off with the NASA probe from Cape Canaveral Air Force Station at 7:05 p.m. Thursday.

There’s an 80 percent chance of favorable weather during a nearly two-hour window at Launch Complex 41, which was undamaged by a SpaceX rocket’s nearby explosion a week ago.

Once safely in space, the spacecraft the size of a small SUV, built by Lockheed Martin, will take two years to journey more than 5 million miles and meet up with the asteroid that Lauretta described as a “small mountain in outer space,” measuring about 1,600 feet across.

From thousands of candidates, Bennu emerged as NASA's ideal target.

The asteroid’s orbit around the sun is close enough to reach. It doesn’t rotate too quickly. And telescope observations show it is carbon-rich, more likely to hold amino acids or other organic compounds left over from the solar system’s formation more than 4.5 billion years ago.

Those factors make it “one of the most fascinating and accessible asteroids,” said Christina Richey, the mission's deputy program scientist at NASA headquarters.

Over two years, a suite of cameras and sensors will create high-resolution, 3-D maps of Bennu’s surface and composition.

UCF, FIT scientists part of OSIRIS-REx mission

“We will be able to see an object the size of a penny,” said Daniella DellaGiustina, lead image processing scientist at the University of Arizona in Tucson. “Scientists will know more about Bennu than we know any other Near-Earth asteroid.”

That knowledge will include the first close-up study of how heat from sunlight gives asteroids like Bennu a slight push, changing their trajectories over time.

Factoring that effect into orbit calculations will help determine if asteroids pose a threat. Bennu itself is classified as a potential hazard, with a 1 in 2,700 chance — or less than one-tenth of 1 percent — of colliding with Earth late in the next century.

After a sampling site is picked, the OSIRIS-REx spacecraft will have as many as three chances to drop down and perform “touch-and-go” maneuvers with its outstretched robotic arm, planned in July 2020.

When a circular container at the end of the arm contacts Bennu's surface, it will release a burst of nitrogen gas that blows material through a filter, trapping it inside.

“We are basically a space vacuum cleaner,” said Lauretta.

Two ounces, or the equivalent of four tablespoons of sugar, is the minimum desired sample, but the container could scoop up more than four pounds.

The arm will stow that precious payload in a return capsule as if in a bank vault. The mission’s sole priority then will be to deliver the material home for detailed laboratory analysis.

On Sept. 24, 2023, the 100-pound capsule — identical to one NASA’s Stardust mission used to bring back comet dust — will plunge into Earth’s atmosphere at 27,000 mph.

A heat shield and parachutes will slow its fall for a soft touchdown at the Utah Test and Training Range, about 80 miles west of Salt Lake City.

NASA will store the rare sample at Johnson Space Center in Houston, and at a “secure location” in New Mexico. The OSIRIS-REx mission will keep only a quarter of it, preserving the rest for future scientists.

“The information we’re going to gain from OSIRIS-REx, it’s really going to help pull back the curtains on the origin of this planet, on the origin of life itself,” said NASA Chief Scientist Ellen Stofan.

Contact Dean at 321-242-3668 or jdean@floridatoday.com. And follow on Twitter at @flatoday_jdean and on Facebook at facebook.com/jamesdeanspace.

Launch Thursday

Rocket: United Launch Alliance Atlas V (411 configuration)

Mission: OSIRIS-REx, NASA's first asteroid sample return mission

Launch Time: 7:05 p.m. EDT

Launch Window: To 9 p.m. EDT

Launch Complex: 41 at Cape Canaveral Air Force Station

Weather: 80 percent “go”

Visit floridatoday.com starting at 4:30 p.m. Thursday for countdown chat and updates, including streaming of NASA TV's launch broadcast.